Designed to fit your device - Keep a spare battery at home, in the office or while travelling so you will never miss that important call. This battery has an extended life and using Lithium Ion technology is protected against the "memory effect". These high capacity replacement batteries are each designed & tested specifically for your phone model. The high capacity battery also enhances battery performance by offering a lower internal resistance for extended life over our standard battery. Due to the extended power of these batteries they come with a phone specific back cover which allows for the larger size. Our batteries are safe to use, identical in size & shape to the original manufacturer"s batteries and far better value.batteries and far better value.